Abstract: A method to evaluate the axial capacity of pile foundation is proposed in which the pile unit skin friction and the unit end bearing resistance are computed from the sleeve friction, excess pore water pressure and effective cone resistance, qe. The component reliability indices based on the ultimate limit state (ULS) and the serviceability limit state (SLS) criteria and the system reliability indices combining ULS and SLS are evaluated. Reliability analysis is conducted to evaluate the performance of the proposed CPTU method. The results show that the proposed CPTU method has higher reliability indices than other three methods. Further assessment of CPTU-based pile capacity in other Jiangsu clay sites should be made. The CPTU method is simple, fast and independent of all operators' subjective influence. Therefore, it is notably suitable for use in pile engineering practice.